Remove usings

Author: davidfowl

src/Hosting/Hosting/src/Internal/HostingApplicationDiagnostics.cs

@@ -1,10 +1,8 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Collections;
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
-using System.Globalization;
 using System.Runtime.CompilerServices;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Http.Features;